1. Field of the Invention
The present invention relates to a wire harness having an electrical wire that has a connector provided to an end portion thereof.
2. Description of Related Art
Traditionally, in a wire harness having an electrical wire that has a connector provided to an end portion thereof, a structure is often employed where a connection terminal crimped to the end portion of the electrical wire is inserted and locked in a terminal insertion hole of the connector (see FIGS. 6A and 6B). In this structure, different types of metal may be used in a lead wire constituting the electrical wire, and the connection terminal. Contact potential difference occurs in an area where dissimilar metals are in contact with each other, and when moisture acting as an electrolyte aqueous solution adheres to the contact area, corrosion may occur on the metal having a lower standard electrode potential.
For example, in a case where a copper connection terminal is crimped to an aluminum electrical wire, when moisture adheres to a contact area thereof, corrosion tends to occur on the aluminum electrical wire which has a lower standard electrode potential.
For this reason, in a case where dissimilar metals are connected to each other, such as in a case where a copper terminal is crimped to an aluminum electrical wire for example, various types of a waterproofing shield are applied to the connection area thereof in order to prevent galvanic corrosion of the connection area (see, for example, Japanese Patent Laid-Open Publication No. 2012-074176, FIG. 3, Paragraph [0016] and Japanese Patent Laid-Open Publication No. 2014-073637, FIGS. 1 and 3).
In Japanese Patent Laid-Open Publication No. 2012-074176, a technology is disclosed in which a corrosion-proofing member 140 is used to prevent electrolytic corrosion of a portion of a terminal-provided electrical wire 120 where metals of a terminal 130 and the electrical wire 120 are in contact with each other (see FIG. 7). The corrosion-proofing member 140 is a long tubular member configured by an adhering portion 142 and a corrosion-proof covered portion 144. The corrosion-proofing member 140 covers a core wire crimped portion 134 of the terminal 130 and a core wire exposed portion 122 of the electrical wire 120 to which the core wire crimped portion 134 is crimped, thereby preventing corrosion of the portion where metals of the terminal 130 and the electrical wire 120 are in contact with each other.
In Japanese Patent Laid-Open Publication No. 2014-073637, a heat-shrinkable tube is disclosed which includes a heat-shrinkable resin tube and an adhesive layer provided to an inner surface thereof, where the adhesive layer is provided to only a middle portion in a lengthwise direction of the resin tube. After a joint portion of an insulation-covered electrical wire is inserted into the heat-shrinkable tube, the heat-shrinkable tube is heated and caused to shrink in a radial direction. The heat causes the adhesive layer to flow and cover the joint portion, and the joint portion is further covered by the shrunk heat-shrinkable tube, thereby waterproofing and corrosion-proofing the joint portion.
However, in a case where the heat-shrinkable tube provided with adhesive (as disclosed in Japanese Patent Laid-Open Publication No. 2014-073637) is used to apply the waterproofing shield to the crimped area of the electrical wire and the connection terminal (as disclosed in Japanese Patent Laid-Open Publication No. 2012-074176), first, the connection terminal crimped to the end portion of the electrical wire is inserted into the heat-shrinkable tube, then, after the heat-shrinkable tube is positioned and fixated so as to adequately cover the crimped area, the heat-shrinkable tube is heated and heat shrunk (see FIGS. 5A-5C). This results in an increase in working man-hours as well as low precision with respect to positioning of the waterproofing shield.